Step-oblique mammography is an accurate technique for determining whether a mammographic finding visible on multiple images on only one projection (but not elucidated using standard additional mammographic projections) represents a summation artefact or a true mass and for precisely localizing the true mass for further evaluation.
Projections are obtained every 15° beginning with the view in which the density is visible. If the density is still not visible with this technique, it can be considered a summation artefact, and no further evaluation is needed.
The diagnostic accuracy of step-oblique mammography will be maximized by carefully observing technical requirements.
- all step-oblique images should be taken with the breast in the same orientation (i.e. all mediolateral oblique or all lateromedial oblique)
- the nipple should be in profile on all step-oblique exposures and there should be no rolling of the breast .
- the patient should stand up straight during all step-oblique exposures.
- projections are obtained every 15° beginning with the view in which the density is visible
- frequently used to assess the non-calcified density identified on only one standard mammographic projection
- helpful in evaluating grouped microcalcifications seen on only one standard view
- helpful in establishing the presence of truly clustered calcific particles
- permitted accurate three-dimensional localization of the lesion
- step-oblique mammography is also useful in indicating the three-dimensional locations of more than one lesion in the same breast, especially if two or more lesions display similar mammographic features and are similar in distance from the nipple; confirmation of the precise three-dimensional location of each lesion by step-oblique mammography permits planning of the optimal approach for imaging-guided biopsy.
- if the density is not visible with this technique, it can be considered a summation artefact, and no further evaluation is needed
History and etymology
It was initially described by K L Pearson et al.
- 1. Pearson KL, Sickles EA, Frankel SD et-al. Efficacy of step-oblique mammography for confirmation and localization of densities seen on only one standard mammographic view. AJR Am J Roentgenol. 2000;174 (3): 745-52. doi:10.2214/ajr.174.3.1740745 - Pubmed citation
- 2. Logan WW, Janus J. Use of special mammographic views to maximize radiographic information. Radiol. Clin. North Am. 1987;25 (5): 953-9. Pubmed citation
- 3. Sickles EA. Combining spot-compression and other special views to maximize mammographic information. Radiology. 1989;173 (2): 571. Pubmed citation
- 4. Feig SA. The importance of supplementary mammographic views to diagnostic accuracy. AJR Am J Roentgenol. 1988;151 (1): 40-1. doi:10.2214/ajr.151.1.40 - Pubmed citation
- 5. deParedes ES. Atlas of Mammography. Lippincott Williams & Wilkins. (2007) ISBN:0781764335. Read it at Google Books - Find it at Amazon